Childproof latch



p 1965 P. L. SPEIGHT ETAL 3,206,238

CHILDPROOF LATCH Filed April 26, 1965 5 Sheets-Sheet 1 3 F-Ke. l I 34 INVENTORS (9 Pam. L. SPEJHT \JE L R.FARNSWORTH Fla 4 ATTORNEY Sept. 14, 1965 P. L. SPEIGHT ETAL CHILDPROOF LATCH 5 Sheets-Sheet 2 Filed April 26, 1965 W F O H W e N S 3 W U N I N m 1 F (v 6 L Q L 1 mm l\ pv/ F Y Q B 8 4 ATTORNEY p 1965 F. L. SPEIGHT ETAL 3,206,238

CHILDPROOF LATCH Filed April 26, 1963 5 Sheets-Sheet 3 PAUL. L..SPE\(=HT VERL R. Faanswoam ATTo RNELY Sept. 14, 1965 P. L. SPEIGHT ETAL 3,206,233

CHILDPROOF LATCH Filed April 26, 1965 5 Sheets-Sheet 4 INVENTORS Paw. L. 39am VERL Q. FARNSW TH ATTO EY Se t. 14, 1965 P. 1.. SPElGHT ETAL 3,206,233

GHILDPROOF LATCH 5 Shets-Sheet 5 Filed April 26, 1963 Ill United States Patent 3,296,238 CHILDPROOF LATCH Paul L. Speight and Verl R. Farnswortb, Milwaukee, Wis., assignors to E. R. Wagner Manufacturing Company, Milwaukee, Wis., a corporation of Wisconsin Filed Apr. 26, 1963, Ser. No. 275,948 15 Claims. (Cl. 292-195) This invention pertains to a latching mechanism for closures such as doors, cupboards, drawers and in particular medicine cabinets wherein this mechanism may be operated with ease by an adult but requires such dexterity of hand and finger movements as to exclude a small child from entering those closures.

The principal object of this invention is to provide a child-proof latching mechanism which may be used in conjunction with a variety of catches for different installations.

This object is achieved by a latching mechanism which to unlatch requires a combination of motions or steps which must be performed simultaneously and in a continuous sequence, these are squeezing with the thumb and index finger, pushing forward or depressing, and rotation of the hand. As will become more apparent from the further description of this mechanism and its operation, the required steps may be performed quite easily and as a matter of course by an adult but are sulficiently intricate and require such dexterity as to be virtually impossible to be performed by a small child.

A further object of this invention is to provide a spring biased latch which is adapted to be secured on either the right-hand or left-hand front face of a sliding glass or mirror cabinet door.

Prior to this invention right-hand and left-hand latches had to be provided for sliding glass doors. This was necessitated because the glass in sliding doors is engaged by the framework of the cabinet only on the bottom and the two sides of the glass thus leaving the glass freely slidable in the upward direction. To properly latch such doors, the latch has to engage the keeper from its bottom side to prevent opening of the door by merely sliding the glass panel upwardly to disengage the latch and thereafter sliding the panel sidewardly to obtain access to the closure. The latches used heretofore were not capable of being used on both left-hand and right-hand applications, because the spring and latch of a left-hand latch would not operably cooperate when used in a right-hand application and vice versa. As will be best understood from the more detailed description in the specification, we have invented a latch which is equally well suited for a right-hand use as for a left-hand use.

Other objects and advantages of this invention will be pointed out in or be apparent from the specification and claims as will obvious modifications of the two embodiments shown in the drawings, in which:

FIG. 1 is a sectional view of a latching mechanism embodying the present invention with the latch in a locked position and the latching mechanism free turning, only a fragment of the door being shown;

FIG. 2 is a sectional view taken on line 2--2 of FIG. 1;

FIG. 3 is a left end view taken from line 3--3 of FIG. 1 and showing the latch operatively engaging the frame of a closure;

FIG. 4 is a fragmentary sectional view taken on line 4-4 of FIG. 3;

FIG. 5 is a fragmentary sectional view of the latching mechanism shown in FIG. 1 with both dogs depressed to the engaged position for operating the latch;

FIG. 6 is a sectional view taken on line 6--6 of FIG. 5;

FIG. 7 is a sectional view similar to FIG. 6 but showing one of the dogs partially depressed with the result that the latching mechanism is free-turning;

FIG. 8 is a plan view of the inside of the cover porgiigsofl knob of the latching mechanism shown in FIG. 9 is a sectional view of a modification of the latching mechanism shown in FIGS. 1-8 and shows the latch in a locked position and the latching mechanism free-turning, only a fragment of the door being shown- FIG. 10 is a fragmentary sectional view of th latch mg mechamsm shown in FIG. 9 with both dogs depressed to enlglaged position for operating the latch;

1s a sectional view tak FIG. 9; en on line 11 11 of FI G. 12 is a sectional view as shown in FIG. 11 but showing both dogs depressed to the engaging position for operating the latch, the hexagonal portion of the spindle being shown in dotted lines;

FI G. 13 is a sectional view as shown in FIG. 12 but showing one of the dogs fully depressed but witli the result that the latching mechanism is still free-turnin FIG. 14 is a fragmentary sectional view taken on liii e 14-14 of FIG. 11 and also showing a fragment of the cover portion;

FIG. 15 is a fragmentary sectional view take 1515 of FlG. 12 and also showing a fragmeiit t i f iiiz cover portion;

FIG. 16 is a fragmentary sectional view of the latchmg mechanism parts as shown in FIGS. 14 and 15, with the dogs in a depressed position but prior to their operat1ve engagement with the spindle;

FIlIGg. 17 is a sectional view taken on line 1717 of FIG. 18 is a fragmentary sectional view of the latch- Y ing mechanism taken on line 18-18 of FIG. 17;

FIG 19 is a plan view of the inside of the cover porgggsorgthlegfnob of the latching mechanism shown in FIG. 20 is a top plan view of the latch mounted on a sliding glass door which is adapted to be opened by sliding in the right-hand direction, a fragment of the door angIltcging mechanism being shown;

. l is a front elevational vi in FIG. 20; ew of the latch shown FIG. 22 is a top plan view of a latch comparable to that shown in FIG. 20, but mounted on a door adapted to be operated by sliding in the left-hand direction;

FIG. 23 is a front elevational view of the latch shown in FIG. 22; and

HQ. 24 is a plan view of the wire spring of the latch when it is removed from the latch, the dotted lines showmg the contour of the spring when it is mounted on the latching mechanism.

Referring to the drawings in particular, FIG. 1 shows a latching mechanism indicated generally at 14 attached to a door 12, or the like. This mechanism includes a latch 10 adapted to be rotated into and out of engaging or latched position with the frame or keeper 11 of a cabinet by the manipulation and rotation of a knob 28 which may turn freely with respect to the latch or engage and turn it by means of safety devices which is the essence of this invention.

Latch 10 is secured to a spindle 16 rotatably mounted within a spindle housing or mechanism mounting means 18 secured to the door 12 in the customary manner as shown at 19. The spindle is held against axial displacement by a shoulder 20 and a retaining ring 22 which bear against oppositely facing parts of the spindle housing.v A segment of the spindle 16 is provided with a plurality of cogs 26 adapted to be engaged by driving mechanism carried by the knob 28 for turning the spindle and operating the latch from latched to unlatched position.

The knob 28 is rotatably and axially slidably mounted on the spindle housing 18 by a bushing portion and is biased to its outward or free-turning position by means of spring 30 which is provided between shoulders 32 on the spindle housing and a ring or plate 34 incorporated within the knob. The outward axial motion of the knob in respect to the spindle housing is limited by means of shoulders 36 on the spindle and an inwardly extending flange 38 on the knob.

Two identical but oppositely related dogs 42 are slidably carried in knob 28 and have button or finger engaging portions 44 extending outwardly through the rim of the knob. The dogs are biased outwardly by means of springs 48 so that portions 46 on their inner ends will drop into a groove 50 in the spindle 16 to hold the knob in the freeturning position. The dogs thus automatically lock the knob in such position as it is moved outwardly by the spring 30 and prevent the knob from being depressed or pushed forward until the dogs are released. The dogs are slidably and swingably disposed within channels 52 in the knob and are guided by spacers 51 on retaining pins 54 which cooperate with slots 56 formed in the dogs to permit the dogs to have angular as well as radial movement. The springs 48 are carried in the knob by pins 58 and engage apertures 59 within the sides of the dogs opposite the slots 56 so that these springs also urge the inner ends of the dogs to swing radially away from the spindle. This radially outward swinging bias is resisted by raised abutments 60 which rest against locating pins 62. As the dogs are depressed (against the bias of springs 48) the portions 46 are disengaged from groove 50 and a limited outward swinging normally takes place as the abutments 66 slide off the locating pins 62 (see FIG. 7). e

Of course to permit such swinging the channels 52 are slightly tapered on one side as indicated at 53.

The dogs each have cog engaging teeth 66 which project toward the spindle and the cogs 26. These teeth are proportioned so that the normal outward swing of the inner ends of the dogs, is enough to keep the teeth from engaging the cogs even if a dog were fully depressed.

The dogs each have a cam surface 63 near the slot 56 and a cam surface 64 on the inner ends. As oppositely arranged, the cam surface 63 of one dog faces the cam surface 64 of the other dog. Thus in the act of fully depressing both dogs the cam surfaces 63 engage the cam surfaces 64 and swing the dogs radially inwardly so that the teeth 66 engage the cogs 26 as seen in FIG. 6. Also, the respective pairs of cam surfaces tend to lock the two dogs into a wrench and prevent the teeth 66 from riding over the cogs 26. If when the knob and dogs are depressed to the cog engaging position (FIG. 6) one of the dogs is released and sufficient pressure is retained on the other to overcome the bias of spring 48 and prevent its inner end from swinging outwardly and away from the spindle, the single depressed dog will not be operable to rotate spindle 16 since its tooth 66 will tend to ride over the cogs 26. This inoperability will result because upon release of one of the dogs the wrench has been destroyed. The knob 28 when rotated with both dogs depressed imparts motion to the spindle 16 and thus latch 10 to successfully operate the latching mechanism.

It is important to nte that throughout the entire manipulation of the knob the finger portions 44 have to be continually depressed. Should only one dog be fully depressed when the knob is in its free-turning position, the portion 46 of the other dog will still be engaging groove 50 and thus resisting any axial movement of the knob. Should both dogs be depressed to disengage the knob from the central spindle, and after some axial movement one dog he released, the spring 48 will bias the inner end of such released dog against the spindle so that it will contact the ends of cogs 26 and prevent the engagement of the teeth 66 of both dogs with cogs 26. Should the dogs Cir be depressed throughout the entire axial movement to dog engaging position and only one of the dogs be released, the other dog even though depressed would normally swing radially outward or ride over the cogs so that its tooth 66 also will be inoperative and no turning action transmitted to the latch.

From the above description it becomes amply clear that this latching mechanism is only operable to actuate latch 10 when: (1) both dogs are simultaneously depressed to release the portions 46 from groove 50; (2) the knob 28 is pressed axially in against spring 30 while both dogs are either pressed in or released; and (3) both dogs are thereafter held in the depressed position during the continued rotation of the knob. The dogs may be only partially depressed to obtain their disengagement from groove 50; however, they have to be fully depressed for engagement of teeth 66 with cogs 26. The release of one or both of the dogs prior to axial movement or during rotation will stop the unlatching action. After unlatching, release of pressure on the knob and dogs will automatically cause knob 28 and dogs 42 to return to the free-turning position shown in FIG. 1 as previously explained.

To facilitate assembly of the above described embodiment of this invention, knob 28 may be constructed of a cover portion 68 and a base portion 70. After subassembly of the various components of the latch mechanism the cover portion may be attached to the lower portion 70 by means of the retaining pins or rivets 54. As seen in FIG. 8, pins 58 and 62 may be integral with cover portion 68.

A modification of the heretofore described embodiment is shown in FIGS. 9l9, the principal difference being that the spindle 72 of the modified embodiment is provided with a hexagonal portion 74 which is adapted to be engaged by dependent gripping faces 76of two identical but oppositely related dogs 78 upon their manipulation in the same manner as described in connection with the first embodiment.

The spindle '72 is rotatable mounted within a spindle housing 86 and held against axial displacement'by a bushing 82 and the bottom face 84 of the hexagonal portion '74. The knob 86 is rotatably and axially slidably mounted on the spindle housing and is biased to its outward or free-turning position by a spring 88 which is provided between a shoulder 90 on the spindle housing and washer 92, the latter in turn is held against shoulder 94 by downwardly extending lugs 96 of a thrust washer 98 (as best seen in FIG. 18).

The dogs 78 are slidably carried by knob 86 and have finger engaging portions 109 extending outwardly through the rim of the knob. The dogs are biased outwardly by springs 102 which are held in grooves 104 in the spindle housing 80 and are retained therein by washer 98. It is also of note that the springs engage the dogs so that the outward bias exerted by them also tends to bias the dogs in a counterclockwise direction (if viewed in FIGS. 11- 13) thus tending to urge the inner ends of the dogs radially away from the spindle. The dogs are slidably carried within channels 106 and guided by spacers 108 which engage slot 110 (FIG. 11) in the same manner as in the first described embodiment.

When the latching mechanism is in the free-turning position (FIG. 11) the springs 102 urge the portions 111 of the inner ends of the dogs against the reduced diameter portion 112 of the spindle so that both or either one of the dogs engages shoulder 114 and prevents the knob from being depressed unless both dogs are pressed inwardly. When the dogs are released from a depressed position, surfaces 116 of the Wall of the aperture 118 guide the dogs to the directly opposing position shown in FIG. 11.

The operation of this latching mechanism is the same in principle as that explained on connection with the first embodiment. As both dogs are depressed when the latching mechanism is in the free-turning position (FIG; 11) the portions 111 of the inner ends of the dogs move out of engagement with spindle portion 112 and upon cam surfaces 120 engaging cam surfaces 122 assume the position as shown in FIG. 12. As seen in this figure sufficient clearance is provided between the portions 111 of the dogs and the spindle 72 to permit depression of the knob 86. Upon depressing the knob while keeping the dogs in a radially inward position face portions 76 will engage two opposite faces of the hexagonal portion 74 of the spindle 72 and will comprise a wrench by means of which the spindle can be turned to successfully operate the latching mechanism. It is apparent that quite often the ends of the face portions 76 will abut against the top face of the hexagonal spindle portion, as in FIG. 16, but that upon a slight turning of the knob, it can be further depressed to permit operable engagement of the hexagonal portion, as in FIG. 15.

As shown in FIG. 13, the release of one of the dogs, while the knob is in the depressed position will permit the face 76 of the released dog to move away from the hexagonal portion of the spindle and render the wrench inoperable, since upon rotation of the knob the face 76 of the depressed dog will swing radially outwardly upon encountering the rises of the hexagonal portion and not impart motion thereto.

After operation of the latch, release of the pressure on the knob and dogs will automatically return the knob and dogs to the free-turning position shown in FIG. 9.

To facilitate the assembly and operation of the above described embodiment of this invention, knob 86 may be constructed of a cover portion 124 and a base portion 126. The cover portion may have integral therewith the guide spacers 108 and pins 128 which engage slots 130 of the thrust washer and serve to secure the thrust washer and the end cap against rotational motion during operation of the latching mechanism.

FIGS. 20-23 show a sliding glass door 132 which is equipped with a child-proof latch embodying our invention of which an extended portion 134 of the spindle is shown. A latch 136 is removable secured to the spindle by a screw 140, or by similar known means, and is biased into engagement with the bottom side of a keeper 142 by wire spring 144. The latch and spring are so designed that the identical parts may be used on a door slidable to the right to open a closure (FIGS. 20 and 21), or may be used on a door slidable to the left to open a closure (FIGS. 22 and 23). In changing the latch from a right-hand use to a left-hand use, the latch is removed from the extending portion 134 of the spindle and inverted around its vertical axis so that its previously exposed outwardly facing surface 146 is turned to face the door 132.

In order to attain this versatility, the spring 144 has to be adapted to provide an equal upward bias to the latch in either position. For this reason the spring 144 is provided with bent end section 148 which engages aperture 149 in the latch and another bent section 150 which passes through a slot 152 in the bottom edge of the latch. The spring has a bridge section 154 between the two bends which contacts the outwardly facing surface of the latch and a downwardly slanted leg 155 extending towards the door 132 and engaging the housing 156 to bias the latch upwardly. As seen from FIG. 24, the spring 144 is bent to some degree in the transverse plane when it is secured to the latch which results in a bias between the end 148 and the inwardly facing surface of the latch and also between a part of the leg 155 and the same surface. This bias aids in fixing the spring to the latch. When the latch is changed from a left-hand to a right-hand use (or vice versa) the spring 144 is removed from the slot 152 and aperture 149 and changed so that the bridge section 154 will contact the other side of the latch thereby placing the leg 155 again in a downwardly, towards the door slanting position.

i As it should be apparent from the drawings, the spring 144 may be easily disengaged from the latch after the latter has been removed from the extended spindle portion 134 by merely sliding the bent portion out of the slot 152 and thereafter pulling the end 148 out of the aperture 149. To secure the spring to the latch, the end 148 is first engaged in the aperture and thereafter portion 150 is engaged in the slot 152.

Although but two embodiments of the present invention have been illustrated and described, it will be apparent to those skilled in the art that various changes and modi fications may be made therein without departing from the spirit of the invention or from the scope of the appended claims.

We claim:

1. A safety latching mechanism comprising,

mounting means for attaching the mechanism to a part to be latched,

a latch movably carried by said mounting means and having a latched and unlatched position,

an operating knob carried by said mounting means for moving said latch from one of said positions to another,

clutch means operable between said knob and said latch, and said operating knob including operating means for said clutch means requiring a first movement and pressure in one direction, a second movement and pressure in a second direction, and a third movement in a third direction while maintaining said pressure in said first and second directions.

2. The mechanism of claim 1 wherein said operating means include a movable dog by means of which said movement in the first direction is imparted.

3. The mechanism of claim 2 wherein there is a plurality of oppositely related dogs on said knob, and biasing means to urge said dogs outwardly of said knob.

4. The mechanism according to claim 1 in which said mechanism includes, first clutch elements connected to said latch, outwardly biased manually operable members carried by said knob and projecting therefrom, said members having second clutch elements, said knob being biased axially in one direction and movable axially in the opposite direction to bring said second clutch elements in alignment with said first clutch elements, said manually operable members being movable inwardly against said bias to engage said first and second clutch elements.

5. The mechanism according to claim 4 in which said manually movable members also have biased angular movement to prevent engagement of said first and second clutch elements, said members having interacting cam surfaces to overcome said biased angular movement upon completion of the relative movements inwardly.

6. A safety latching mechanism comprising,

mounting means for attaching the mechanism to a part to be latched,

a latch movably carried by said mounting means and having a latched and unlatched position,

an operating knob carried by said mounting means for moving said latch from one of said positions to another,

clutch means operable between said knob and said latch, said operating knob including operating means for said clutch means requiring a first movement and pressure in one direction, followed by a second movement and pressure in a direction towards said clutch means, said second movement followed by a rotary movement while maintaining pressure in said first and second directions, said rotary movement being transferred by said clutch to said latch to thereby move said latch from one position to another.

7. A safety latching mechanism comprising,

mounting means for attaching the mechanism to a part to be latched,

a spindle rotatably carried by said mounting means,

a latch attached to said spindle and movable thereby between a latched and unlatched position,

an operating knob carried by said mounting means and movable in an axial direction in respect to said spindle,

clutch means carried by said spindle,

operating means for said clutch means requiring a first movement in a transverse direction in respect to the axis of said spindle, a second movement of said knob in the axial direction, and a rotary movement of said knob while maintaining pressure in said transverse and said axial directions on said knob to thereby transfer said rotary motion by said clutch means to said spindle.

8. A safety latching mechanism comprising,

mounting means for attaching the mechanism to a part to be latched,

a spindle rotatably carried by said mounting means,

a latch attached to said spindle and movable thereby between a latched and unlatched position,

an operating knob carried by said mounting means and movable in an axial direction in respect to said spindle,

manually operable members biased in an axial directionin respect to said spindle and carried by said knob and projecting therefrom, said members engaging said spindle to prevent motion of said knob in one axial direction in respect to said spindle,

clutch means carried by said spindle,

engaging means for said clutch means requiring a move ment of said manually operable members in a transverse direction in respect to the axis of said spindle thereby disengaging said member from said spindle, thereafter'a movement of said knob in said one axial direction to thereby engage said engaging means with said clutch means, said engaging means and clutch means cooperating to move said latch to said unlatched position upon rotary movement of said knob while maintaining pressure in the transverse direction on said manually operable members and pressure in said one axial direction on said knob.

9. A safety latching mechanism comprising,

mounting means for attaching the mechanism to a part to be latched,

a spindle rotatably carried by said mounting means,

a latch attached to said spindle and rotatable thereby between a latched and unlatched position,

engaging means carried by said spindle,

an operating knob rotatably carried by said mounting means and movable in an axial direction in respect to said spindle,

biasing means for biasing said knob in a direction away from said engaging means,

outwardly biased manually operable means carried by said knob and projecting therefrom in a direction transverse to the axis of said spindle, said manually operable means engaging said spindle to prevent axial motion of said knob in a direction towards said engaging means,

said manually operable means disengaging from' said spindle when said means are moved inwardly and forming a wrench which operably engages said engaging means after axial movement of said knob towards said engaging means, thereby transferring rotary motion of said knob to said latch.

10. A safety latching mechanism according to claim 9 wherein said manually operable means comprise two oppositely positioned members, said members having portions disposed in said knob which engage substantially opposite sides of said engaging means when said members are moved inwardly and said knob is moved axially towards said engaging means.

11. A safety latching mechanism according to claim 10 wherein said members are pivotally secured within said knob, said members having surfaces which engage each other and prevent pivotal motion of said members when both members are moved inwardly,

12. A safety latching mechanism comprising,

mounting means for attaching the mechanism to a part to be latched,

a spindle rotatably carried by said mounting means,

a latch attached to said spindle and rotatable therewith between a latched and an unlatched position, said spindle having a section with a plurality of opposite faces,

an operating knob rotatably carried by said mounting means and movable in an axial direction in respect to said spindle,

biasing means biasing said knob away from said section of the spindle,

two outwardly biased manually operable members slidably and pivotally carried by said knob and projecting therefrom on opposite sides of said knob in a direction transverse to the axis of said spindle, said members engaging said spindle to prevent axial motion of said knob in a direction towards said faces and being disengageable therefrom in response to their movement inwardly, said members having cam surfaces which engage each other upon inward movement of said members and which lock said members against pivotal motion, said members also having contoured sections which upon the engagement of said cam surfaces form a wrench of a size adapted to operably engage said faces of the spindle, said wrench operably engaging said faces of the spindle upon movement of said knob towards said faces thereby transferring rotary motion of said knob to said latch.

13. A latching mechanism according to claim 12 wherein said section having said opposite faces is in the form of a nut, and wherein said contoured sections of said members engage opposite sides of said nut to impart rotary motion thereto.

14. A latching mechanism according to claim 12 wherein said latch has an aperture and a slot in its bottom edge, and wherein said latch is biased upwardly against the bottom side of a keeper by a wire spring removably secured to said latch and having one of its ends engaged in said aperture, having one section engaged in said slot, and having its other end positioned against a member secured to the part to be latched.

15. A latching mechanism for use with closures having sliding panel doors comprising,

mounting means for mounting the mechanism to a panel door which is slidable in one direction to open the closure,

a latch removably securedto said mounting means and movable between latched and unlatched positions, means for moving said latch between said positions, said latch being biased into engagement with the bottom side of a keeper by an elongated spring, said latch having an aperture and a slot on its bottom edge, said spring being removably attached to one side of said latch by having one of its ends engaged in said aperture, having a section engaged by said slot, and having its other end positioned against stop means incorporated in said mounting means and cooperating with said spring to bias said latch upwardly, said latch being invertible around its vertical axis and said spring being attachable to the other side of said latch for mounting the mechanism to another panel door slidable to open a closure in the opposite direction from the first mentioned door.

References Cited by the Examiner UNITED STATES PATENTS M. HENSON WOOD, JR., Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 3,206,238 September 14, 1965 Paul L. Speight et ale It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 7, line 21, for "an axial" read a transverse Signed and sealed this 29th day of March 1966,

test: 5

{NEST SWIDER EDWARD J. BRENNER testing Officer Commissioner of Patents 

1. A SAFETY LATCHING MECHANISM COMPRISING, MOUNTING MEANS FOR ATTACHTING THE MECHANISM TO A PART TO BE LATCHED, A LATCH MOVABLY CARRIED BY SAID MOUNTING MEANS AND HAVING A LATCHED AND UNLATCHED POSITION, AN OPERATING KNOB CARRIED BY SAID MOUNTING MEANS FOR MOVING SAID LATCH FROM ONE OF SAID POSITIONS TO ANOTHER, CLUTCH MEANS OPERABLE BETWEEN SAID KNOB AND SAID LATCH, AND SAID OPERATING KNOB INCLUDING OPERATING MEANS FOR SAID CLUTCH MEANS REQUIRING A FIRST MOVEMENT AND PRESSURE IN ONE DIRECTION, A SECOND MOVEMENT AND PRESSURE IN A SECOND DIRECTION, AND A THIRD MOVEMENT IN A THIRD DIRECTION WHILE MAINTAINING SAID PRESSURE IN SAID FIRST AND SECOND DIRECTIONS. 